name = ['zzy','zch','zsy']
print(name)
cant = name.pop(2)
print(f'{cant} can\'t come today')
name.append('wxg')
print(name)

name.insert(0,'zch')
name.insert(2,'a')
name.append('b')
print(name)

print(f'I have invited {len(name)} customers to my party.')
# 练习3.9
